Power supply system

1. A power supply system comprising:

a system control unit configured to operate using electric power supplied from a main power supply, so as to control an operation of a system that performs a desired function, the system control unit comprising one or more first processors programmed to execute functions of the system control unit;

an auxiliary power supply provided separately from the main power supply and configured to provide assistance in supply of the electric power to the system control unit according to a status of supply of the electric power from the main power supply; and

an auxiliary-power-supply control unit configured to control a status of supply of the electric power to the system control unit from the auxiliary power supply such that the assistance is provided, the auxiliary-power-supply control unit comprising a second processor programmed to execute functions of the auxiliary-power-supply control unit,

wherein the system control unit and the auxiliary-power-supply control unit are configured to output information of at least one control unit of the system control unit and the auxiliary-power-supply control unit to another control unit of the system control unit and the auxiliary-power-supply control unit, and

wherein the at least one control unit is configured to output information indicating that an operation of the at least one control unit is stopped to the other control unit when the at least one control unit stops the operation of the at least one control unit.

2. The power supply system according to claim 1 , wherein:

the status of the supply of the electric power from the main power supply and an operation status of a mounting destination of the system are correlated with each other; and

the at least one control unit is configured to determine whether the operation of the at least one control unit is to be stopped based on the operation status of the mounting destination of the system, and to output information indicating that the operation of the at least one control unit is stopped to the other control unit when the at least one control unit determines that the operation of the at least one control unit is stopped.

3. The power supply system according to claim 1 , wherein:

in a case where one control unit of the system control unit and the auxiliary-power-supply control unit is a first control unit, and another control unit of the system control unit and the auxiliary-power-supply control unit is a second control unit,

the first control unit is configured to receive information indicating an operation status of a mounting destination of the system from an external control unit that is provided in the mounting destination of the system separately from the system control unit and the auxiliary-power-supply control unit such that the operation status of the mounting destination of the system is able to be determined;

the first control unit is configured to output information indicating that the first control unit stops an operation of the first control unit to the second control unit when determining that an operation of the mounting destination of the system is stopped, on a condition that stopping of the operation of the mounting destination of the system is determined using the information indicating the operation status of the mounting destination of the system when the first control unit stops the operation of the first control unit; and

the second control unit is configured to determine whether an operation of the second control unit is to be stopped using the information indicating that the first control unit stops the operation of the first control unit, the information being input from the first control unit.

4. The power supply system according to claim 1 , wherein the system control unit and the auxiliary-power-supply control unit are configured to determine an operation status of a mounting destination of the system using a source voltage as information indicating the status of the supply of the electric power from the main power supply.

5. The power supply system according to claim 1 , wherein:

the auxiliary power supply provides the assistance in the supply of the electric power by backing up the supply of the electric power to the system control unit instead of the main power supply on a condition that there is a decrease in the electric power supplied from the main power supply;

the power supply system further comprises a selection circuit provided between the main power supply and the auxiliary power supply, and the system control unit, the selection circuit being configured to select the electric power from one of the main power supply and the auxiliary power supply such that the electric power is supplied to the system control unit, the one of the main power supply and the auxiliary power supply having a higher supply voltage than a supply voltage of another of the main power supply and the auxiliary power supply; and

the auxiliary-power-supply control unit is configured to control the auxiliary power supply such that the electric power from at least the auxiliary power supply is supplied to the system control unit via the selection circuit while the main power supply supplies the electric power to the system control unit.

6. The power supply system according to claim 5 , wherein the selection circuit includes:

a first diode that is provided in a first power supply path which is a path for supplying the electric power from the main power supply to the system control unit; and

a second diode that is connected to a portion of the first diode provided in the first power supply path, the portion of the first diode being located on a side of the system control unit, and the second diode being provided in a second power supply path which is a path for supplying the electric power from the auxiliary power supply to the system control unit.

7. The power supply system according to claim 1 , wherein:

the system is a steering system that is mounted in a vehicle and functions to operate at least one of a steering wheel and a turning wheel which are provided in the vehicle; and

the system control unit is configured to control an operation of the steering system.